The increase of the popularity of the soft contact lenses has led to many proposals for their manufacture. This is especially true because current contact lens manufacture employs a number of discrete processing steps. First, a monomer, of an appropriate material having good optical properties when polymerized, is placed into a female mold. A male member is then placed over the mold, much as described in U.S. Pat. No. 4,640,489. The monomer is then polymerized by exposing the mold to ultraviolet light or by heat.
After polymerization, the lens is removed from the mold and hydrated by immersion in a bath. Generally this bath is comprised of a buffered salt solution with a surfactant. After hydration, the lens is washed and placed in a saline solution. Thereafter, the finished lens is packaged and made available for consumer use.
It has been recognized however, that current hydration processes can be quite long and time consuming. After placing the lenses in a wash tank, the lenses must be drained, rinsed and brought to equilibrium in an isotonic saline solution.
Current hydration processes use large volumes of water contained in several large tanks through which the lenses must be moved by large machinery. During processing the lens may sometimes become inverted. In these instances it will be necessary for a worker to touch the lenses to reinvert them. This is especially true in systems where lenses are manually transferred to the final package. This human interface is slow, expensive, and can damage the lens.